Consistent acetaldehyde issues

[Joejkd82]

I'm on my 50th batch or so. I brew all grain 2 gallon batches. I use mr beer fermenters for all my brews, and I keg into a 2.5 and a 3 gallon keg.

I am having trouble with acetaldehyde creeping into 90% of all my beers 3 weeks after primary and getting WORSE with age.

These seems to be no rhyme or reason to it. It's happened in a 1.071 Og IPA a 1.075 old ale and now to a 1.051 pale ale

At first I thought maybe it was temperature so I started fermenting at lower temps in my basement which is about 65 degrees in the Summer. This works about half the time. Now, this winter my basement is too cold for ales So I'm back upstairs in a spot that is 63 to 65 degrees.

I always pitch one packet at dry yeast. I've had the problem with us 05 and s 04 as well as Lallemand's s 05 equivalent

Oddly enough the only liquid yeast I've ever used was WLP 300 for hefeweizen (twice) and I've never had a problem with those.

I've tried purging my kegs before racking to them but that doesn't seem to make a difference.

The problem exhibits itself consistently in the brews it manifests itself in.. acetaldehyde odor and flavor becoming apparent after 3 weeks in primary and becoming stronger with age. The wierd part is that it doesn't seem to matter whether I keg at that time or let it continue to sit in primary the same thing happens. One of the kegs is used but the other is brand new and the issue happens in both. This is so frustrating it makes me want to quit brewing. I let one age for an extra month once and it made no difference whatsoever.

The only consistent factors are the fermenters I'm using and that it seems to happen more in my kitchen than my basement regardless of temperature.

I really want to save this latest batch as it tasted excellent 2 weeks after primary.

Does anyone have any advice on how I Can prevent or treat this? I'm at my wits end. My brews taste excellent the few times this doesn't happen to me, it's the only flaw I typically have.

 

[RD400F]

Are you making starters? For bigger beers you definitely need to make a starter. I was having the same problems with my Belgians and it was all because of me not stepping the yeast up to do the job.

 

[mrboz]

I had that problem with a couple beers, but I found that it was due to not properly finishing my beers and drinking them while they were still young. I've started making D-rests a pretty standard part of my routine and also giving the yeast more time to clean up after itself. You are making pretty high gravity beers so wonder if you could benefit from more time and/or perhaps a good yeast starter.

However, you say that the problem gets worse with more time. In that case, it sounds like it could be an oxidation issue. Although you say that you purge your kegs when transferring, make sure that you dont splash your beer when you rack.

Good luck and dont give up.

 

[smarek82]

How is your fermentation? Does it get off to a quick start? Have you tried yeast nutrient? My guess would be maybe not enough oxygen in the wort. Splash around when transferring to your fermenter to get some oxygen into solution for yeast metabolism. Then the same goes what others said. If your tasting stale it could be post fermentation oxidation. Good luck. Diacetyl rest shouldn't matter since you're already fermenting in mid 60's.


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[Joejkd82]

I get fast fermentations. Most of my 05 batches reach final Gravity in 5 days and attenuate well.

I am pitching full dry yeast packs into 2 gallon batches so there are plenty of cells.

 

[shuckit]

Try less yeast.

 

[dannysk]

Generally speaking, acetaldehyde (AA) is a function of three things:

1. Yeast strain - This does not seem to be the case for you based on what you described. Coors yeast is the classic example as AA is a defining part of its flavor profile.
2. Not enough yeast - Also does not seem to be the case based on what you described. Typically, after the primary fermentation, there will be a natural peak of AA and as the beer ages it will be reduced. A normal function of aging with the right amount of yeast, at the right temperature and if the yeast is healthy.
3. Unhealthy yeast - In this case, as the yeast die/lyse, AA increases and it will never go back down. Other factors that ultimate relate to the health of the yeast are: (a) if there is too much yeast (not enough good nutrition per yeast cell). So after all "good stuff" is consumed, they will die out; (b) too high of a temperature during secondary/aging; (3) poor yeast nutrition, especially look to use a nutrient that has zinc. There are many other factors but look at yeast health and how this is impacted, e.g., amount of yeast, wort make up, temperature, aeration levels, etc. Without knowing more of the details it would only be a guess but reason #3 above (IMO) is clearly the issue.

I also disagree that O2 introduction (unless it was several dissolved ppm) is a factor.

Don't give up... think yeast health.

Good Luck. Cheers.

 

[flars]

You mention ambient temperature, but what is the wort temperature over the first three days of fermentation?
High gravity beers like yours can have a rise in wort temperature of 8° to 10° during active fermentation when an entire pack of yeast is pitched to two gallons of wort.
The WLP300 most likely had less viable yeast cells than the full packs of SA05 and SA04.

 

[Joejkd82]

Ferm temp never exceeded 68 deg.

I've done quite a bit of research and I think I can pin the cause on one from a few factors during my brew process:

1.) Zinc deficiency: I don't think this is it as the flavor doesn't manifest itself for weeks after primary has finished

2.) Overpitching: too much growth, not enough fermenting. Don't think this is it, see number 1.

3.) Hot side aeration: stick with me here. I don't have a tube for my mash tun, so the wort comes flying out the valve about 2 feet into my boil kettle. Now I know some people think this is a myth, but it does cause oxygen retention that manifests itself weeks after brewing. One such effect of this internal oxygenation is the production of acetaldehyde.

4.) Ambient temps too cold: I pitch at 69 degrees but ambient is usually about 60 to 62. Don't think this is causing it

5.) Cooling beer too fast to serving temp: I have no idea why this would cause it but I read it in a thread (that of course I can't find) that someone suggested cooling beer too rapidly could be a cause. I suppose I do this, so if this does cause excessive acetaldehyde, this would be a culprit.

Could this be it? I brewed a belgian dubbel 2 weeks ago and the fermenter already wreaks of the stuff. I hope it goes away but I know it probably won't and it's driving me nuts. I have an imperial ipa in my other fermenter right now that is 8 days old that tastes phenomenal already and has a stabilized fg. I bet in another week this will be acetaldehyde city, too.

Should I cut the yeast I pitch in half and dose some yeast nutrient? I have well water that is quite high in iron, could this be it?

What is causing this? If its yeast health, why doesn't it show up until well after primary is finished? I really think it might be the design of the mr beer fermenters or hot side aeration.

Thoughts?

 

[Aonghus]

My understanding is that Acetaldehyde is an intermediate compound of which alcohol is the desired end result. Have you tried rousing your yeast by gently swirling the fermenter? Did your yeast all floc out too soon? I think the others are correct about the health of your yeast and that you ought to use nutrients and 02 in your cooled wort. Do you dry pitch the sachet or do you hydrate the yeast, prior to pitching? If you hydrate the yeast, you need to keep the temperature of the water cool enough to not kill cells.

 

[Manzier]

According to the yeast book.

1. Removing from yeast to early (you're not cold crashing it before it conditions right)
2. Oxidization after fermentation.
3. Bacteria
4. Fast fermentation due to over pitching or high temps


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[smarek82]

I would try less yeast as others have suggested, but I think I remember reading somewhere that during anaerobic metabolism yeast use glycolysis and acetylaldehyde is a byproduct of converting the sugar to alcohol. Which leads me to believe you don't have enough oxygen needed for optimal yeast metabolism. Or maybe you do and the over pitching is using it up. I'm not a microbiologist so please no one bash me if I am way off!!!


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[RmikeVT]

I have to go with infection on this one. I had a similar experience, every other brew I did for a little while had a funky taste. I typically cycle through 3 fermentors as I have multiple batches going at a time and I tracked back all the off brews to the same fermentor. I cut it out of the rotation and started doing a better job cleaning and problem solved.

I also think infection because it is getting worse over time. You got a bug in there working away. Its tough for them to get established when they are competing with yeast, but once the yeast drop out and get out of the way, the bugs are converting stuff to acetylhyde(sp).

Go pick up a bucket at your LHBS or 3g Better Bottle and ferment in that and see if you have a problem.

 

[Joejkd82]

Def not an infection, far too consistent. Also, the taste is not sour and additional drops in Gravity are not observed.

I pitch right into the wort, no hydration.

I am not cold crashing, I generally have my brews in primary 3 to 4 weeks then keg them and let condition cold an additional week or two.

I believe oxidation or overpitching to be the culprit. I don't see where the oxidation is occurring aside from hot side aeration.

I have good fast fermentations, so overpitching seems to be possible.

I believe I will try my next batch with some yeast nutrient. If that fails, ill pitch a half packet. If that fails, ill stop the splashing on the hot side. If that fails, ill try a different fermenter.

I'll add in each solution one at a time until I figure out what works.

 

[Wallonia]

I can understand how you must be frustrated -- especially if your beers taste promising during early fermentation.

1) Why do you attribute the problem to acetaldehyde? Can you give an aroma / taste description?

2) Any other off flavors? Over attenuation?

3) Did I understand correctly that you are splashing your wort from mash tun to boil kettle? This could easily be avoided.

4) Have you ever brewed a bad batch with liquid yeast? If not, then you know your brewing process isn't to blame.

Good luck and hang in there.

 

[Joejkd82]

1.) I believe it's acetaldehyde because the flavor and aroma smells like fresh cut green apples. After conditioning it fades a touch but it stops fading and is the to stay.

2.) None that I can tell

3.) Yes, I'm buying some tubing so this doesn't happen.

4.) No, never, but I've only ever used wlp300 and that was twice.

Wierd thing is I did an imperial ipa 2 weeks ago with us05 and it's tasting perfect, no off flavors at all. I didn't do anything differently, so I have no idea why this is the case. I wish I knew why this leaves every 5th batch or so alone....

 

[Manzier]

Must be very frustrating. With the hot side oxidisation this shouldn't be a problem. It will taste like paper or cardboard if that was the problem. It's oxidisation after fermentation that can cause the dreaded green apple. Or so I believe.


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[Black Island Brewer]

Wierd thing is I did an imperial ipa 2 weeks ago with us05 and it's tasting perfect, no off flavors at all. I didn't do anything differently, so I have no idea why this is the case. I wish I knew why this leaves every 5th batch or so alone....

Just thinking out loud here. If overpitching is the problem, then a IIPA would be less likely to have been overpitched. This, combined with not having the problem with the liquid yeast, could point to overpitching being the problem

 

[Joejkd82]

You might be right there. I figured a Belgian dubbel with a half pound of candi sugar would be safe from that (used t 58 on that one). So if I pitch a half packet, what do you do with the rest?

 

[pvault98]

I noticed one point was glossed over and that is that you are pitching the yeast dry into the wort. According to Jamil, this results in half the yeast dying instantly. I don't use dry yeast, but I know that it is extremely important to hydrate them first in cool enough water. I think if you use the Mr Malty or other pitching calculators and determine the correct amount, hydrate your yeast, and oxygenate you should be in much better shape. Yeast health is the main factor behind acetaldehyde staying behind in the beer and not being cleaned up.

 

[BreezyBrew]

As soon as I read the thread title, I thought over pitching as others have suggested. The one time I had the same problem I had accidentally made my starter way too large and too high gravity which resulted in too many cells. The beer tasted great until I kegged and waited two weeks. Pitching the correct theoretical amount of cells with fresh yeast was the biggest improvement on my beer.

The only other thing I can think of is to keep your trash can far away from you beer if you brew in your kitchen.

 

[Joejkd82]

Dry yeast hydration on the homebrew scale is a well debated topic. I also doesn't explain how my imperial ipa came through unscathed. Could be the reason, but id say is unlikely the reason

 

[Oskar]

@Joejkd82 I would like to know how did it turn out at the end. Any progress identifying the cause?

OT: I started having similar problems in my last 3 batches, but I'm not sure if it is acetaldehyde or extracted tannin. My beer does definitely have a bit different odour, but not green-apple like. I would say that 10% problem is smell, and 90% astringent taste. I'm blaming my mashing process, but I have some doubts.

 

[Aonghus]

Dry yeast hydration on the homebrew scale is a well debated topic. I also doesn't explain how my imperial ipa came through unscathed. Could be the reason, but id say is unlikely the reason

Could it be that the Imperial came through ok due to the high gravity?
That is, it may not have been over pitched for an Imperial.

 

[Facinerous]

I gotta say, I'm a little bit stumped on this one. In your OP you are saying that the acetaldehyde smell/flavor is increasing over time after having kegged the beer. From everything that I know acetaldehyde is generated from a few different ways, active fermentation, and yeast death.

In my mind, since the flavor is developing after the active fermentation it sounds like everything you are doing before transferring to keg is going well. If you had the apple smell taste in the early stages then most, along with me, would guess its generated from the active fermentation. Lets rule that out though.

So the next main thing to look at would be yeast death in my opinion. I have read through this thread and saw a few things that look like a potential possibility. One is initial aeration of the wort. I don't remember that being addressed. The yeasts health will be directly effected by this. Second is nutrients, which has been addressed. Last, which I don't remember anyone asking. Do you cold crash before kegging?

Last, but maybe the most likely suspect in my opinion really is sanitation. Aceto bacteria can and will cause a cidery taste, and once its there there is nothing that can be done about the taste. In my opinion since its a taste that is getting stronger over time after the primary fermentation, this would be your most likely culprit. What you are using to transfer from primary vessel to keg, or even the keg itself may have some little jerks lingering around waiting to ruin a good batch of beer.

 

[Gameface]

I too think this sounds more like acetobacter. Green apple and apple cider vinegar could be mistaken for one another pretty easily, especially if you are in denial about the possibility of an infection.

 

[Radboud]

Thread CPR'ed, I hope you don't mind

I too experience AA for too often; I used to use dry yeast exclusively and always underpitched (as per the instructions on the packets).

I recently did a BIAB beer using 33% corn grits (aka polenta) just to get some experience with adjuncts. I made a starter this time but still detect AA in the beer; reading this thread I might have overpitched and I also might have cold crashed it too early.

I used a 2L starter made with Wyeast 2124 Bohemian Lager, 48h on a stir plate and decanted. This went into 3 gallons of 1.054 wort which fermented at 18ºC / 64.4ºF down to 1.009 (which is kind of low for this strain but that I chalk up to the corn providing loads of fermentable sugars) in about a week. On the hot side of this strain but still should be clean. Then I did a D-rest for another week at 20ºC / 68ºF. Cold crashed, fined with gelatin and moved (under pressure, I ferment in cornies) to a purged keg. It spent 2 weeks in the keezer. When I took a sample earlier today I detected the AA, aroma and taste, cidery acidity.

I will try and pitch the correct amount of cells next time.